懦 (nuò): This character is about character and feeling. The left side is the “heart” radical (忄), which is used in many characters related to emotions and thoughts. The right side (需) primarily provides the sound. Together, you can think of it as a “weakness of the heart” or a hesitant character.
弱 (ruò): This character means “weak.” Pictorially, it's said to represent two bent bows (弓), which lack the tension and strength of a proper bow. It signifies a lack of physical or metaphorical strength.
When combined, 懦弱 (nuòruò) creates a powerful image: a weakness of the heart (懦) compounded by a general state of weakness (弱), resulting in a personality that is fundamentally cowardly and spineless.
In Chinese culture, both traditional and modern, courage (勇敢, yǒnggǎn) and strength of character (坚强, jiānqiáng) are highly esteemed virtues. Heroes in history, literature, and film are defined by their bravery and willingness to face adversity. Consequently, being labeled 懦弱 (nuòruò) is a serious criticism of one's character.
A useful comparison in Western culture is the difference between “timid” and “spineless.”
Timid (胆小, dǎnxiǎo): This is closer to being shy or easily frightened. It's often seen as a personality trait, especially in children, and doesn't necessarily carry a heavy moral judgment.
Spineless/Cowardly (懦弱, nuòruò): This is a moral failing. It implies a person knows what is right but lacks the courage to act on it. It suggests they are unreliable under pressure and will abandon principles to save themselves. While an action can be “cowardly” in English, 懦弱 is more often used to describe a person's entire disposition. It's the antithesis of the cultural ideal of a hero (英雄, yīngxióng) or a person of integrity.